The present invention relates to cooling units for electronic circuitry, and particularly concerns the mounting of cooling fans to electronic circuit housings. Illustrative embodiments relate to, but not exclusively to, cooling units for use with computer systems.
Electronic circuitry, and particularly processor circuitry, is susceptible to performance deterioration if it is allowed to operate outside an ideal temperature range. In some circumstances electronic circuits can even fail due to an excess of heat. Electronic circuitry is conventionally contained in a sheet metal housing. The housing may be mountable in a larger supporting rack, to enable circuits to be connected together in modular form.
To reduce the likelihood of electronic circuitry overheating, it is possible to provide forced cooling by using cooling units. For example, a computer system can comprise electronic circuitry housed within a casing. Typically, the casing includes at least one vent or aperture that can be located on any face of the casing, but is typically in the front or the rear of the casing, adjacent to which a cooling unit, for example a fan unit, is mounted. Fans are operated to drive cooling air into the housing containing the electronic circuitry, thus displacing heated air from within the housing through the vents or apertures and into the surrounding environment.
Conventional cooling fans used in electronic equipment comprise a pair of spaced end frames, which are generally square in shape, joined by a circular-section duct in which is mounted an axial-flow fan, with its driving motor in the fan hub. The corners of the end frames are provided with mounting holes through which rivets, screws or other fasteners can be engaged to secure the fan to the equipment housing. The fan is secured with its duct in alignment with an opening in the housing, so that air moved by the fan can flow into the housing to cool the components of the circuit.
Although simple in construction, cooling fans may fail prematurely in their operating lifetime, and require to be replaced. This operation typically involves removing the fasteners which fix the fan to the equipment housing, disconnecting an electrical connection, and finally removing the faulty fan. A replacement fan is mounted by locating the fan in place and fixing it using fasteners, then connecting an electrical lead to the equipment housing. This two-stage process is time consuming for the maintenance operative, and cannot usually be entrusted to an unskilled operator.
A need therefore exists for a fan which may be rapidly and easily removed from, and located and secured to, a housing of an electronic circuit.